[WIP] Support Fitbit Subscription

[jzhou59]

Work done

• Subscription setup for users to receive data
• Endpoints setup done
• User repository

Next steps

• YR send test server access to Fitbit rest sources
• Create services to process the data
  • Create Fitbit endpoints and capture notifications received from fitbit subscription API.
  • Store the data from Fitbit subscription in redis — it contains the callback URLs
  • Run a service to read data from redis and make requests (similar to backfill implementation)
• Converters to convert data received from Fitbit to RADAR-Base Avro format to ingest into Kafka
  • PR from Joris the rest connector
  • YR: Still need to publish to maven
• Auth Validators
  • Check for userId in the user repository
  • Any other things we can use to authorise the data coming in
• Configuration
  • Subscriber ID
  • Binding jersey

[yatharthranjan]

Work moved to #52